Tuned With 192* Stat

So I'm trying to search out if my original tune with my 192* stat is
affecting my rich idle conditions,because i switched to a 180* later.
Both O2's have been replaced and I have "NO CODES" in either KOEO/KOER modes.
Idles great, runs strong etc, no stalling, no issues nothing, just rich at idle.

...so I've been using 93 octane and was thinking that I wasn't getting a clean burn because of the 10* at idle.
So i went to 90 octane and nothing changed at idle except it raised it slightly because it's reacting to my higher compression and it's more sensitive to combustion etc.
I get some slight pinging up high on the RPM's when I get into it, but normal driving I have no issues with that octane.

side note:
still have stock Alternator in, so my charging system is probably lower than expected with the electric fan, but that wouldn't make the fuel pump demand more, it should be less right??

Fuel pressure holds strong after engine cut off for a good 40min, no slow drop in psi until 8-10 min later.

I feel like my options are limited with the no codes, what do you think about these??
a) replace ECT coolant sensor to a more newer, sensitive one.
b) add a aftermarket 6al or crane mult-spark ignition
c) change the stat back to 190* .....any other ideas????

Do you have a wideband? 180 thermostat will make your motor run a little cooler, that could make a difference in your tune. Is it a custom tune? Put a stock t stat back in and fix the real cooling issues. 180 stat is a bandaid.

I don't have a wideband. Yes it's a custom dyno tune.
I upgraded the stock radiator because my stock one leaked. Went to a 3 row copper/alum and thought why not go to a cooler stat too. Just never thought it would it would mess with my tune, but I think it has.
Never had any cooling issues before or after the radiator upgrade. Just noticed a small leak in the upper part.
I do believe the 180* stat is telling the ECT coolant sensor to dump more fuel also. So I guess that is what I'll have to do.

So I forgot that I actually increased the spark plug gap to .039-.040 to see if the ignition would like it. So I lowered the gap back down to .033, ....(believe .035 was the original setting from the chip tune). Then added 89 octane to help clean up the burn while hoping the advanced timing, when i get into the pedal doesn't create pinging, which it hasn't so far.

So these 3 things did however raise the idle some, not much but it did.
1) New ECT sensor (coolant sensor, not temp sensor)
2) .033 on the spark plug gap (heads are milled 30/1000 so compression is higher)
3) going from 93 to 89 octane, kinda scared to go 87 with the chip tune

oh i did lower the fuel psi from 41 psi to 38psi
really trying to delay a T-stat change with the summer upon us

so i'm gonna do the ole base idle reset and see where she's at, hopefully burning cleaner at idle.

I think you have a case of the stinky exhaust just like any other mustang without smog equipment. Even with my car idling at 14.6 afr it still stinks, you do not have cats to help burn the unburnt fuel in the exhaust. My bone stock vert has no cats, stinks, it has all of the other smog equipment on it though.

So I added the 192* stat back this weekend. While I was at it I upgraded the t-stat housing with the threaded temp sensor bung to add an aftermarket gauge later. Right now I got it hook up to the stock gauge to see how it's responding. Waiting for the t-stat to open is kinda fun....haha, but I reset the computer to help make the switch from 180* extra cool(extra rich) to more normal operating temperature. I do not have cats so any change in unburnt fuel is very noticeable, especially in this parking deck at start up. From the nose test, it seems to have helped a good bit. Waiting to get a few more computer cycles under the belt to see where it's really at.

A 180* t-stat will not cause changes in any of the symptoms described in this thread. When you start the car, the EEC performs a lot of self checks then idles initially in open loop. REGARDLESS OF TEMP.

If the car is at operating temperature and sensor readings are within tolerances, then the EEC will switch to closed loop.

With what is described so far in this thread, nothing you've done has changed any of that. Without specific alteration to the EEC, a 160* (that one-six-zero) t-stat can prevent going into closed loop. A 180* t-stat-though is far into what the EEC would consider safe territory for closed loop operation and would have no effect. What's more.... No t-stat on the planet is going to change the start up sequence of the EEC.

So 180* or 192*... It really doesn't matter where the described symptoms in this thread are concerned. Catalytic converter as suggested by f8tlfiveo though... will DEFINITELY affect your calibrated nose sensors when starting up or sitting at a stop light.

There are other things that also cause changes to the sniffer check. Have you tried pulling codes to see if anything else has changed?

Additionally (and this is just a note) 91 octane gas does not increase your compression over 87 or 89. Nor does it burn any hotter, brighter, better, or (insert your favorite internet myth here). All higher octane pump gas does is resist detonation resulting from compression. If your motor is not knocking or pinging at wide open throttle at operating temp then you gain nothing from higher octane gas.

It has been rich at stop lights etc, not just at start up. But I could smell it faster being in a parking deck, even when i pulled into the deck and parked. I know 87, 89 octane IS more volatile than 93 octane. Higher octane resists detonation, so going from 93 to 91 will help to get a more complete burn. I never said it would raise compression, however my compression is raised from my heads being milled 30/1000 so that would aid a lot more in burn potential than a regular compression engine. I thought I stated that clearly. I have no codes btw. However I moved the TPS wire when it was idling and the idle speed changed so I'll have to look into replacing it soon.

No t-stat on the planet is going to change the start up sequence of the EEC.
All higher octane pump gas does is resist detonation resulting from compression. If your motor is not knocking or pinging at wide open throttle at operating temp then you gain nothing from higher octane gas.

Click to expand...

I agree with this, I knew this, I don't know why I didn't tell you this before..

Well since the 192* change from 180*, ...I've been at plenty of red lights, coming and going here in the parking deck and it's running WAY less rich. I don't have cats so it helped my situation out at least, just throwing it out there.